Mixed Langmuir Monolayers of Gramicidin A and Ethyl Palmitate:  Pressure−Area Isotherms and Brewster Angle Microscopy

The amphiphilic TEMPO molecules consist of two dissimilar parts. One part is hydrophilic (head) and the rest part is hydrophobic (tail). The derivatives of 4-alkaneamino-2, 2, 6, 6-tetramethyl-1-piperidinyloxy radical ( C n-amino-TEMPO, n = 14, 16, 18, 20, 22) was synthesized with 4-amino-TEMPO and carboxylic acid. The C n-amino-TEMPOs equilibrated at the air/water interface form Langmuir monolayer by classical Langmuir monolayer techniques. The stable monolayers of C 14-22-amino-TEMPOs were characterized by pressure–area isotherms. The features of collapse pressure of C 14-22-amino-TEMPOs were confirmed on alkyl chain length. Limiting area points and take-off area points from surface pressure-MMA isotherms were subjected to the influence of subphase. The monolayer of C 22-amino-TEMPO which has longer alkyl chain was characterized by Brewster Angle Microscopy. So we can confirm phase transition by BAM images as monolayer is expanding at the room temperature.

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Behavior of Syndiotactic Poly(methyl methacrylate) Monolayers at the Air/Water Interface: Influence of Temperature and Molecular Weight on the Surface Pressure−Area Isotherms and Brewster Angle Microscopy Images

The Journal of Physical Chemistry C ◽

10.1021/jp904848c ◽

2009 ◽

Vol 113 (40) ◽

pp. 17455-17463 ◽

Cited By ~ 11

Author(s):

José Miñones ◽

Mercedes Miñones Conde ◽

Eva Yebra-Pimentel ◽

José M. Trillo

Keyword(s):

Molecular Weight ◽

Methyl Methacrylate ◽

Surface Pressure ◽

Brewster Angle ◽

Water Interface ◽

Brewster Angle Microscopy ◽

Influence Of Temperature ◽

Air Water Interface ◽

Pressure Area ◽

Microscopy Images

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Fresnel formula for optically anisotropic Langmuir monolayers: an application to Brewster angle microscopy

Langmuir ◽

10.1021/la00003a004 ◽

1995 ◽

Vol 11 (3) ◽

pp. 699-704 ◽

Cited By ~ 31

Author(s):

Yuka Tabe ◽

Hiroshi Yokoyama

Keyword(s):

Langmuir Monolayers ◽

Brewster Angle ◽

Brewster Angle Microscopy ◽

Fresnel Formula

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Head-group Dependent Domain Morphologies in Langmuir Monolayers

Bangladesh Journal of Scientific and Industrial Research ◽

10.3329/bjsir.v46i1.8104 ◽

1970 ◽

Vol 46 (1) ◽

pp. 47-52

Author(s):

MM Hossain ◽

T Kato

Keyword(s):

Phase Transition ◽

Langmuir Monolayers ◽

Brewster Angle ◽

Head Group ◽

Critical Surface ◽

Brewster Angle Microscopy ◽

Head Groups ◽

Air Water Interface ◽

Surface Morphologies ◽

Internal Texture

The effect of head groups on the thermodynamic properties and morphological features of the domains formed in the Langmuir monolayers at 10 oC has been investigated by a film balance and a Brewster angle microscopy (BAM). 2-hydroxyethyl myristate (2-HEM) and n-tetradecanoyl N-ethanolamide (NHEA-14), having the same chain length but different head groups have been taken as amphiphiles. Both the amphiphiles represent a first-order LE-LC phase transition at 10 oC at the air-water interface. The critical surface pressure necessary for this phase transition is 6.0 mN/m for 2-HEM and 1.0 mN/m for NHEA-14. The surface morphologies of the domains are entirely different. The domains of 2-HEM are circular having internal texture, while those of NHEA-14 are dendritic having directional characteristics. The presence of interfacial hydrogen bonding in the latter amphiphile should be responsible for the formation of such characteristic domains in the case of latter amphiphile. Key words: Langmuir monolayers; Phase transition; Brewster angle microscopy; 2-hydroxyethyl myristate; n-tetradecanoyl Nethanolamide. DOI: http://dx.doi.org/10.3329/bjsir.v46i1.8104 Bangladesh J. Sci. Ind. Res. 46(1), 47-52, 2011

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